Behavioral manipulation of retrieval in a spatial memory task for Drosophila melanogaster

A paradigm for operant conditioning of freely walking single Drosophila flies has been described previously. A fly can be conditioned to avoid one side of a small test chamber if the chamber is heated whenever the fly enters this side. In a subsequent memory test without heat the fly continues to avoid the previously heat-associated side. In this experimental design one cannot exclude that flies mark the heated side by an odor that they subsequently avoid during the test. As a final proof for associative learning in the present experiment, flies are trained in one chamber and tested for learning in another, similar one. Handling in the transfer experiment interferes with memory display, even if the fly is returned to the old chamber instead of a new one. Memory can be reactivated, however, by subjecting the fly to an additional brief training (priming), which is too short to establish significant learning in naive flies. For efficient priming, heat has to be applied to the same side as during training in the old chamber. Only then the fly subsequently shows a side preference and avoids the side of the new chamber, which in the old one had been associated with heat. The two chambers are similar but not identical The transfer experiment therefore raises the question as to what the flies use as spatial reference during training and test. In the light, they can be shown to orientate according to visual landmarks associated with the chamber. In complete darkness, where training and memory scores do not differ from those in the light, they are assumed to use a combination of tactile and idiothetic information for orienting.     

Cue competition effects in the planarian

The learning abilities of planarian worms (Dugesia tigrina) were assessed by using a number of Pavlovian conditioning paradigms. Experiment 1 showed that planaria were susceptible to basic conditioning in that they readily developed a conditioned response to a change in ambient luminance when it was consistently paired with an electric shock over a number of trials. In Experiment 2, the change in luminance was presented in a compound with a vibration stimulus during conditioning. Subsequent tests revealed poor conditioning of the elements compared with control groups in which the animals were conditioned in the presence of the elements alone, an instance of overshadowing. In Experiment 3, pre-training of one of the elements before compound conditioning resulted in blocking of learning about the other element. These results add to other studies that have reported cue competition effects in animal species belonging to different phyla (chordate, mollusk, arthropod), suggesting that learning in these phyla could be ruled by similar principles. The results are discussed adopting an evolutionary-comparative approach.     

Avoidance of heat by rats: Effects of thermal context on rapidity of extinction

Rats were trained to avoid radiant heat in a one-way, jump-up apparatus. The animals that could avoid heat responded more frequently and more rapidly than did yoked controls that received heat, but for whom no avoidance contingency was deliberately arranged. Control animals trained with light, rather than heat, did not learn to avoid. Using this jump-up avoidance, rats were trained to avoid heat in a room maintained at 27°C. They were then given a series of extinction trials, with no heat presentations, with the temperature maintained at either 27 or 7°C. Placing the rats in a cold environment facilitated extinction of heat avoidance behavior, but only in animals that had previously experienced heat while they were in the cold. Prior heat experience administered in a warm, rather than cold, context was not sufficient to potentiate the effect of ambient temperature on avoidance extinction. Implications of these results for theories of avoidance learning are discussed.     

Behavioral assessment of pain detection and tolerance in monkeys

Cebus albifrons monkeys received electrical stimulation of the hindlimbs over a wide range of intensities. On trials signalled by a blue light, the animals were permitted to escape shock by pressing a disc, or shock was terminated after 8 sec (free escape). Escape force (disc pressure) was found to increase as stimulation intensity increased well beyond escape threshold, while shock duration curves reached plateau at the mid-range of intensities. The shock duration curves generated by free escape responses should be comparable to pain detection functions obtained by similar operations in humans, and the curves were stable over months of testing, as is generally found in pain-detection studies. On trials signalled by a red light, the animals received intense tail shock immediately after escape responses (punished escape), or, if they endured leg shock for 8 sec without escaping, then they could avoid tail shock with a panel press. The shock duration curves generated by punished escape responses should be comparable to pain tolerance functions as defined for human subjects, and the escape thresholds were considerably higher on red-light trials. As in human studies, the tolerance curves were not stable over repeated testing sessions, and some feature of the paradigm forced a progression toward extremely high levels of tolerance.     

Second-order optional avoidance as a function of fixed-ratio requirements

Two rhesus monkeys responded on a fixed-ratio schedule in Stimulus 1 (blue light) to avoid the onset of Stimulus 2 (green light). Failure to avoid Stimulus 2 required a second fixed-ratio performance to avoid Stimulus 3 (red light) in the presence of which unavoidable shock occurred. Relative frequencies of avoidance performance in the blue light and in the green light were inversely related to the ratio requirement under each stimulus condition. Both differential response-cost and avoidance-failure probability factors were related to the observed changes.     

On the perpetuation of ignorance: system dependence, system justification, and the motivated avoidance of sociopolitical information

How do people cope when they feel uninformed or unable to understand important social issues, such as the environment, energy concerns, or the economy? Do they seek out information, or do they simply ignore the threatening issue at hand? One would intuitively expect that a lack of knowledge would motivate an increased, unbiased search for information, thereby facilitating participation and engagement in these issues-especially when they are consequential, pressing, and self-relevant. However, there appears to be a discrepancy between the importance/self-relevance of social issues and people's willingness to engage with and learn about them. Leveraging the literature on system justification theory (Jost & Banaji, 1994), the authors hypothesized that, rather than motivating an increased search for information, a lack of knowledge about a specific sociopolitical issue will (a) foster feelings of dependence on the government, which will (b) increase system justification and government trust, which will (c) increase desires to avoid learning about the relevant issue when information is negative or when information valence is unknown. In other words, the authors suggest that ignorance-as a function of the system justifying tendencies it may activate-may, ironically, breed more ignorance. In the contexts of energy, environmental, and economic issues, the authors present 5 studies that (a) provide evidence for this specific psychological chain (i.e., ignorance about an issue → dependence → government trust → avoidance of information about that issue); (b) shed light on the role of threat and motivation in driving the second and third links in this chain; and (c) illustrate the unfortunate consequences of this process for individual action in those contexts that may need it most.     

A Light Theory with Heavy Burdens

In “ A Light Theory of Color”, Walter Sinnott-Armstrong and David Sparrow argue that color is neither a primary quality of objects, nor a disposition that objects have, nor a property of our visual fields. Rather, according to the view they present, color is a property of light. The present paper aims to show, first, that the light theory is vulnerable to many of the very same objections that Sinnott-Armstrong and Sparrow raise against rival views. Second, the paper argues that the strategies that Sinnott-Armstrong and Sparrow use to avoid certain objections are also available to proponents of rival accounts. This might only seem to show that the light theory is in the same shaky boat as other theories: suffering from the same problems but having the same tools for solving them. The paper concludes with a suggestion as to why this is not the case, but why the existence of the light theory is nevertheless likely to bring increased clarity to the debate about color realism.     

Learned suppression of photopositive tendencies in Drosophila melanogaster

A task was designed to teach individual flies to avoid a lighted area after they had displayed an initial preference for it. The flies walked in a T-maze and chose between a lighted and a darkened alley leading, respectively, to a lighted and a darkened vial. Flies that were photopositive on a first trial were subjected to an aversive stimulus (a filter paper inserted into the lighted vial and wetted with a quinine solution), and they performed 16 training trials; they learned to avoid the lighted vial. The flies trained with water instead of quinine in the lighted vial still display avoidance of the lighted vial, but to a lesser extent. The flies trained with a dry filter paper in the lighted vial did not show any increase in avoidance during training. Like the flies trained with no quinine at all, those trained to avoid the lighted vial under a partial reinforcement condition (one half of the trials with quinine, the other half with a dry vial) did not master the task. Finally, removal of the quinine after an avoidance acquisition criterion was reached resulted in an extinction process.     

Increasing conspicuity on night-time roads: Perspectives from cyclists and runners

Pedestrians and cyclists are at significant risk of being killed as a result of a collision with a vehicle at night-time because of their poor conspicuity. Retroreflective strips positioned on the moveable joints, in a biological motion configuration (biomotion), greatly enhance the night-time conspicuity of pedestrians and cyclists, but it is not clear how widely this strategy is adopted among those running and cycling under low light levels (dawn and dusk or at night). This study explored runners’ and cyclists’ beliefs about their own conspicuity, and the strategies they use to increase their conspicuity and safety under low light levels.Nine focus groups involving 50 participants (mean age = 39.5 ± 13.9 years) were held with individuals who ran and/or cycled under low light conditions or at night-time. The strategies that participants used to increase their conspicuity and enhance their personal safety, and the importance they placed on increased conspicuity to other road users at night was explored. Data were analysed thematically, with two main themes identified. Strategies describes the different approaches used to increase conspicuity when running or cycling in low light, some of which are ineffective. Importance describes how conspicuity relates to other considerations that influence cyclists and runners. While they may believe that conspicuity is essential for their safety, they may compromise their own conspicuity by prioritising style or comfort, or because they believe that being more conspicuous is of limited value because it cannot compensate for the behaviour of other road users.In summary, cyclists and runners are largely unaware of effective strategies to increase their night-time conspicuity, particularly the use of biomotion reflective strips. Garment manufacturers should ensure that conspicuity features (with supporting educative product information on labels) are incorporated into cyclists’ and runners’ clothing or accessories to improve wearer conspicuity and hence safety in low light conditions.     

The role of a nonparticipant observer in drug abuse field research

The development of a "nonparticipant observer" role in research on youthful drug use is described. The role proved valuable in gathering the kinds of information considered necessary by Becker (1955) and others for building theories of deviant behavior. The researcher had some access to the group prior to the project, and various interventionist actions on behalf of the youth helped increase the level of acceptance. The resulting rapport and confidence enhanced the research role, making possible penetration of the protective "fronts" of the deviant subjects. While dual functions of researcher and interventionist complemented each other, they presented personal role conflicts that had to be resolved. By assuming the role of nonparticipant in the deviant behavior itself, the researcher could avoid many moral, legal and ethical dilemmas without betraying either his own values or his objectivity. The author believes it is incumbent upon such a researcher to describe the uniqueness of his role so that his objective findings may be properly appraised in light of his subjective involvement.     

Getting Expression‐Based Semantics Right: Its Proper Objects of Evaluation and Limits

Often those attempting to resolve the answering machine paradox appeal to Kaplan's claim that the objects of semantic evaluation are expression‐types evaluated with respect to indices, instead of utterances, as part of their solution. This article argues that Dylan Dodd and Paula Sweeney exemplify the kind of mistakes theorists make in applying such expression‐based semantic theories in that (1) they conflate what is asserted with semantic content, and (2) they take their approach to utterance interpretation as having semantic significance. In light of these mistakes, we learn two things. First, we learn how expression‐based semantic theorists can avoid making these kinds of mistakes. Second, we learn how the limits of expression‐based semantics can contribute to what we should expect a semantic theory to explain regarding how semantics fits into a more general theory of linguistic communication and linguistic understanding.     

Attitudinal ambivalence and message-based persuasion: motivated processing of proattitudinal information and avoidance of counterattitudinal information

Attitudinal ambivalence has been found to increase processing of attitude-relevant information. In this research, the authors suggest that ambivalence can also create the opposite effect: avoidance of thinking about persuasive messages. If processing is intended to reduce experienced ambivalence, then ambivalent people should increase processing of information perceived as proattitudinal (agreeable) and able to decrease ambivalence. However, ambivalence should also lead people to avoid processing of counterattitudinal (disagreeable) information that threatens to increase ambivalence. Three studies provide evidence consistent with this proposal. When participants were relatively ambivalent, they processed messages to a greater extent when the messages were proattitudinal rather than counterattitudinal. However, when participants were relatively unambivalent, they processed messages more when the messages were counterattitudinal rather than proattitudinal. In addition, ambivalent participants perceived proattitudinal messages as more likely than counterattitudinal messages to reduce ambivalence, and these perceptions accounted for message position effects on amount of processing.     

Financial resources and decisions to avoid information about environmental perils

Environmental perils pose threats that require mitigation. Mitigation requires knowledge of the threat. Ironically, people may opt to avoid information about an environmental peril, especially if they lack resources to respond and the mitigation burden is high or costly. Three experiments (N = 845) examined how available resources and the resource burden of responding to an environmental peril affect the perceived of burden of taking action, and how perceiving burden, in turn, affects avoidance of information about the threat. Experiments 1a and 1b revealed that lower perceived likelihood of taking action and low income predicted a greater tendency to avoid hurricane risk information among Florida residents. Experiment 2 examined receptivity to information about home radon levels and manipulated the burden required to make repairs ($200 vs. $2,000). Having low income and learning repairs were costly corresponded with greater perceived burden of taking action, which predicted a lower likelihood to repair and greater information avoidance. These findings demonstrate that facing a high mitigation burden and lacking resources can lead to remaining uninformed about risks posed by environmental perils. Remaining uninformed is problematic because it may increase people's vulnerability to damage from these threats. However, these findings also identify a potential pathway for intervention. Reminding people of resources they may be unaware of will likely increase their likelihood of preparation and decrease information avoidance.     

Constitutivism,Error, and Moral Responsibility in Bishop Butler's Ethics

In his writings on moral philosophy, Bishop Joseph Butler adopts an identifiably “constitutivist” strategy because he seeks to ground normativity in features of agency. Butler's constitutivist strategy deserves our attention both because he is an influential precursor to much modern moral philosophy and because it sheds light on current debates about constitutivism. For example, Butler's approach can easily satisfy the “error constraint” that is often thought to derail modern constitutivist approaches. It does this by defining actions relative to the kind of being who performs them, instead of relative to the circumstances of their performance. This gives Butler a conceptually stable account of something that is both fully an action yet morally bad, for which an agent might be held morally responsible. Should modern constitutivists wish to model their views on Butler's in order to satisfy the error constraint, they need not adopt all his theological and other commitments, but they will have to avoid the currently popular constitutivist strategy of deriving normative force from the inescapability of a given principle.     

The effect of reinforcement differences on choice and response distribution during stimulus compounding

In Experiments I and II, rats were trained to respond on one lever during light and another during tone. The absence of tone and light controlled response cessation. In the multiple schedule of Experiment I, all reinforcements were received for responding in tone or light; in the chain schedule of Experiment II, all reinforcements were received in no tone + no light for not responding. Experiment I subjects, for which tone and light were associated with response and reinforcement increase, responded significantly more to tone-plus-light than to tone or light alone (additive summation). Experiment II subjects, for which tone and light were associated with response increase and reinforcement decrease, responded comparably to tone, light, and tone + light. Thus, additive summation was observed when stimulus-response and stimulus-reinforcer associations in tone and light were both positive, but not when they were conflicting. All subjects in both experiments responded predominantly on the light-correlated lever during tone + light, even when light intensity was reduced in testing. Furthermore, when a light was presented to a subject engaged in tone-associated responding, all subjects immediately switched the locus of responding to the light-correlated lever. No change in locus occurred when a tone was presented to a subject engaged in light-associated responding, irrespective of the stimulus-reinforcer association conditioned to tone. The light-lever preference in tone + light indicates that the heightened responding observed in Experiment I was not the summation of tone-associated behavior with light-associated behavior. Rather, it appears to be the result of a facilitation of one operant (light-associated responding) by the reinforcement-associated cue for the other.     

Conformity in a generative linguistic task: the role of category and strategic nonword use.

Marsh, Ward, and Landau (1999) demonstrated that participants asked to create novel words use elements of sample nonwords they are given, even when instructed to avoid use of the examples. In four studies, we replicated the effect of conformity to sample nonwords and found the effect was not influenced by the semantic category of the words unless those words shared orthographic characteristics. We found that although we could increase conformity to examples when word exemplars were grouped by category, it was likely that much of this increase was strategically driven. We propose that the presence of the sample non-words, presented in groups with the same word rules, created an orthographic category used by participants in the word creation task.     

Function word repetitions emerge when speakers are operantly conditioned to reduce frequency of silent pauses

Beattie and Bradbury (1979) reported a study in which, in one condition, they punished speakers when they produced silent pauses (by lighting a light they were supposed to keep switched off). They found speakers were able to reduce silent pauses and that this was not achieved at the expense of reduced overall speech rate. They reported an unexpected increase in word repetition rate. A recent theory proposed by Howell, Au-Yeung, and Sackin (1999) predicts that the change in word repetition rate will occur on function, not content words. This hypothesis is tested and confirmed. The results are used to assess the theory and to consider practical applications of this conditioning procedure.     

A solid state CFF apparatus

In past critical fusion frequency (CFF) experiments, one of two methods for generating the flashing light has typically been used: a strobe light or a motor-driven sectored disk that chops the light from a lamp. Both of these methods generate noise that can cue a subject. A solid state apparatus has been designed to avoid this and other deficiencies of currently used methods. In use, the apparatus has been found to be simple, flexible, and reliable, and it does not give the subject acoustic cues to flicker rate.     

AVOIDANCE BEHAVIOUR TO LIGHT IN THE PROTOZOA TETRAHYMENA: The effect of a gradual versus an abrupt boundary between dark and light

B ergström , S. R. Avoidance behaviour to light in the Protozoa Tetrahymena. The effect of a gradual versus an abrupt boundary between dark and light. Scand. J. Psychol ., 1969, 10 , 81–88.—Samples of Tetrahymena, trained to avoid light, were placed in the dark part of a partially lighted chamber. The frequency of animals entering the lighted part through a gradual and through an abrupt boundary between dark and light was observed. It was found that a gradual boundary was a much more effective obstacle to the animals than an abrupt one.     

Working memory,math performance,and math anxiety

The cognitive literature now shows how critically math performance depends on working memory, for any form of arithmetic and math that involves processes beyond simple memory retrieval. The psychometric literature is also very clear on the global consequences of mathematics anxiety. People who are highly math anxious avoid math: They avoid elective coursework in math, both in high school and college, they avoid college majors that emphasize math, and they avoid career paths that involve math. We go beyond these psychometric relationships to examine the cognitive consequences of math anxiety. We show how performance on a standardized math achievement test varies as a function of math anxiety, and that math anxiety compromises the functioning of working memory. High math anxiety works much like a dual task setting: Preoccupation with one’s math fears and anxieties functions like a resource-demanding secondary task. We comment on developmental and educational factors related to math and working memory, and on factors that may contribute to the development of math anxiety.